1. Technical Field
The present invention relates to a detection method for detecting a communication state based on communication quality values measured for packets transmitted and received within a packet network, a detecting device adopting the detection method, a reference value calculating device related to the detection method, and a recording medium storing a computer program for realizing the detecting device. The present invention relates particularly to a detection method, a detecting device, a reference value calculating device and a recording medium, which enable highly reliable detection of a communication state without being influenced by congestion that occurs temporarily.
2. Description of Related Art
Communication systems such as IP phones using packet networks including a VoIP (Voice over IP) network have become popular. In order to manage the communication quality over packet networks such as a VoIP network, there is a method for detecting a communication state and monitoring a packet network by measuring communication quality values such as delay times of packets transmitted and received within the packet network and comparing the measured communication quality values with a management reference value preset by a network manager.
In addition, Japanese Patent Application Laid-Open No. 2000-41039 discloses a method for automatically calculating a management reference value from the average and standard deviation of values measured in the past. In the method disclosed in Japanese Patent Application Laid-Open No. 2000-41039, an average x and a standard deviation σ of the measured values are calculated, and the value of x+2σ that is a range including about 95% of the measured values is set as a management reference value. Then, by comparing values measured thereafter with the management reference value, a communication state is detected and the packet network is monitored.